Simultaneous administration of live attenuated measles vaccine with DTP vaccine.

Live attenuated measles vaccine was administered to Cameroonian children 12 to 39 months of age alone or with either diphtheria-tetanus toxoids or diphtheria and tetanus toxoids and pertussis (DTP) vaccine. Among children who were initially seronegative for measles hemagglutination inhibition antibodies, seroconversion rates and postvaccination geometric mean titers were similar in all groups. Pertussis antigen in the DTP vaccine was judged to be potent by laboratory potency testing and serologic response in recipients of the vaccine. Thus, the two vaccines may be administered simultaneously without compromising their immunogenicity. These results allow greater flexibility in planning individual or mass immunization schedules.

Smallpox surveillance in Bangladesh: II - Smallpox facial scar survey assessment of surveillance effectiveness.

A smallpox facial scar survey of 465 892 persons aged 0-19 years was carried out in Bangladesh in 1976, covering approximately 1% of the 0-19 year old population. Of the 4 306 persons found with facial scarring consistent with previous smallpox infection, none had a history of smallpox with onset after the last reported case on October 16, 1975. Histories taken from persons with facial scars allowed smallpox incidence to be estimated for each year from 1972 to 1975. These estimates indicate that completeness of reporting increased steadily from 11.8% in 1972 to 83.0% in 1975, reflecting the increasing effectiveness of surveillance.

Immunization, oral rehydration therapy and malaria chemotherapy among children under 5 in Bomi and Grand Cape Mount counties, Liberia, 1984 and 1988.

As part of an evaluation of child survival programmes in 13 African countries, cluster surveys were carried out in two Liberian counties in 1984 and 1988 to measure use of three primary health care services: immunization of infants, antimalarial treatment of children with fever, and oral rehydration of childhood diarrhoea. Immunization rates increased (30-53% for DPT-1 and 13-33% for measles), treatment of malaria with drugs available in the home increased from 5 to 35%, and home use of sugar-salt solution to prevent dehydration remained essentially unchanged, 5.9% in 1984 and 3.8% in 1988.

Smallpox surveillance in Bangladesh: I - Development of surveillance containment strategy.

A major epidemic of Variola major with an estimated 90 000 cases and 18 000 deaths occurred in Bangladesh in 1972. During a 3-year period methods of active surveillance (market search, outbreak investigation, and house-to-house search) were developed to supplement the passive reporting system. The percentage of smallpox cases detected increased from 11.8% in 1972 to 83% in 1975. Together with the implementation of improved methods of outbreak control, smallpox transmission was interrupted in October 1975.

Evaluation of a mass measles immunization campaign in Yaoundé, Cameroun.

A mass measles immunization campaign carried out in Yaoundé, Cameroun, has been evaluated. Sixty per cent of the children were immune to measles at the time of the campaign. Only 51% of the susceptible children received vaccine. This was caused by a lack of attendance at the vaccination centres and errors in the selection of children given vaccine. The vaccine administered was relatively ineffective: 40% seroconversion. Difficulties which probably contributed to the low seroconversion rate included sub-optimal vaccine titre, inadequate doses of vaccine, and the relatively long time of vaccine utilization under tropical temperatures. Overall, 83% of the vaccine given to the vaccinating team was wasted. Future immunization campaigns can be improved through better screening of the children, improved handling of the vaccine, the use of marker vaccines, and improved health education.

Sensitivity of poliomyelitis surveillance in India.

OBJECTIVE: To estimate the sensitivity of poliomyelitis surveillance in India. DESIGN: A comparison of two sets of data obtained from lameness surveys and routine surveillance system. METHODS: Lameness surveys were undertaken by the Ministry of Health and Family Welfare in 1981, 1989 and 1992 using 30-cluster sampling technique. These data were compared with the number of polio cases reported through routine surveillance system. RESULTS: Based on the 1981 survey which was undertaken near the initiation of routine immunization with oral polio vaccine (OPV) in India, poliomyelitis incidence was estimated at 25 cases per 100,000 population. Subsequent studies in 1989 and 1992 estimated a decrease in incidence rates to 15.7 and 6.3 cases per 100,000 population, respectively. Comparing the number of reported cases with the survey estimates provided a measure of the sensitivity of (completeness of reporting) surveillance; the sensitivity increased from 8% in 1981, to 20% in 1989, to 32% in 1992. CONCLUSION: The results are encouraging when compared with the global estimates of 10% reporting in 1993. Nevertheless, there is a need for further improvement in the completeness of reporting of poliomyelitis cases to detect all the cases of acute flaccid paralysis to allow epidemiological investigations and effective follow-up action which is critical to interrupt wild virus transmission.

Sensitivity of neonatal tetanus surveillance system in India.

OBJECTIVE: To estimate the sensitivity of neonatal tetanus (NNT) surveillance in India. DESIGN: A comparison of two sets of data obtained from NNT mortality surveys and routine surveillance system. METHODS: NNT mortality surveys were undertaken in 1981, 1989 and 1992 using 30 cluster sampling technique. The data on reported incidence of NNT through routine surveillance system was taken from the published documents of Health Ministry and WHO. RESULTS: In 1981, the incidence of disease in a national survey was estimated to be 4 and 16.4 per 1000 live births in urban and rural areas, respectively. Follow up surveys in 1989 and 1992 estimated the overall incidence as 4 and 1.74 per 1000 live births, respectively. Comparing the reported and estimated by surveys, around 10% of NNT cases were reported. CONCLUSIONS: There is an urgent need to strengthen the routine surveillance system which at present grossly under-reports the NNT incidence in India.

Immunization opportunities taken and missed.

A significant proportion of nonvaccination is the result of the failure of the health system to make use of every opportunity for immunization. Answers to the four questions: Who is not vaccinated? Where could vaccinations have been given? When could vaccinations have been given? and Why were vaccinations not given? are important to understanding the epidemiology of nonvaccination.

Evaluating immunization services.

PIP: The purpose of evaluating immunization programs is to measure progress made toward predetermined objectives. These objectives include access, immunization delivery, coverage, and disease reduction. Evaluation should be carried out at the operational level, the district level, and the national level. Guidelines for delivery level examination include: meeting all scheduled immunizations; sufficiency of vaccines; checking and recording refrigeration temperatures on a daily basis; screening of all patients for vaccination status; and comprehensive instructions for guardians of each child as to the need for future immunizations and return visits. Monthly evaluation guidelines concern percentages of target group immunizations and the identification of preventable diseases in the immunized group. The questions of which actions will prevent these diseases, as well as how to better inform the public regarding the importance of immunizations are part of the monthly evaluation. National level evaluation should focus on subunit performance and national progress toward objectives. Direct monitoring is effective in evaluating subunit performance as is indirect monitoring through examination of monthly reports. The 5 areas that should be monitored in evaluating national progress are strategies, training, logistics, coverage, and disease reduction. The data used in these evaluations include: information about the pre-immunization status of a population; epidemiologic data; data on vaccination coverage; and data on vaccine effectiveness; and changes in disease occurrence. Personnel responsible for immunization at different levels should not be given a cumbersome methodology. Clear, simple questions should be developed that allow accurate, easy data collection. This allows for evaluation of progress, identification of problems, and the implementation of solutions.^ieng

Mass measles control in West and Central Africa.

PIP: Further attenuated measles vaccine has been given to 13 million children in 19 West and Central African countries as part of a regional program of smallpox eradication and measles control. Measles transmission has been significantly reduced in most countries and interrupted only in Gambia. Analysis of measles cases in the post-campaign period has identified measles in nonparticipants in the mass campaign, new susceptibles, and in a small number of vaccines. Although the original program envisioned recycling, the immunization of new susceptibles, every 2-3 years, epidemiological investigation has indicated that the frequency of recycling must be increased to achieve effective control. The current development of maintenance programs is directed at maximum utilization of mobile teams and static health facilities to achieve immunization of new susceptibles every 6 months in high density population areas and every 12-18 months in low density areas. (author's)^ieng

Urban hospital and rural village smallpox in Bangladesh.

Smallpox mortality at Dacca, Bangladesh Infectious Diseases Hospital during 1972 and 1973 was 46 per cent. To determine if this was the actual rate within the population, data were compared to those collected from village populations in Noakhali District. Age/sex adjusted smallpox mortality for the rural population was 23 per 100 cases as compared to 52 per 100 for the hospital population. Analysis of the difference identified a selection bias of the hospital for severe disease.

Immunofluorescence staining for detection of variola virus.

In September 1975 Bangladesh was the only country in the world with endemic variola major, and the eradication of the disease was imminent. A rapid and accurate laboratory diagnostic method was required to supplement immunodiffusion in agar gel and culture on chorioallantoic membrane of embryonated egg available at the Institute of Public Health in Dacca, Bangladesh. To determine its effectiveness, a new, improved immunofluorescence (IF) staining technique was introduced. Laboratory specimens (scabs or vesicular or pustular impressions) were collected from patients who had, or were suspected of having, smallpox. Seventy-eight of 144 specimens collected were found to be IF positive for smallpox. As the number of laboratory-positive cases far exceeded the number of clinically diagnosed smallpox cases, IF-positive cases were reinvestigated and subsamples of the IF-positive specimens were tested at a World Health Organization poxvirus reference laboratory at the Centers for Disease Control in Atlanta, Ga. The results indicated 100% sensitivity for the IF technique (no false-negative results) in diagnosing variola major but also showed a high rate of false-positive results. Consequently, IF could not be recommended as a routine screening test for smallpox.

Measles control in Yaounde: justification of a one dose, nine month minimum age vaccination policy in tropical Africa.

For tropical countries the World Health Organisation recommends a single dose of measles vaccine, administered at a minimum age of 9 months. In some African nations, however, up to 26% of all reported measles occurs before the age of 9 months, and many African nations have been reluctant to follow the WHO recommendation. In 1974 the Ministry of Health of the United Republic of Cameroon made several changes in the existing measles control strategy, including increasing the minimum age for measles vaccination from 6 to 9 months. Surveillance of measles in Yaounde, the capital city, during the five years after the increase in age at vaccination did not reveal a need to return to the minimum age of 6 months. In fact, by 1979, with measles vaccination coverage among children 12-23 months of age at 40%, there had been a 44% decrease in reported measles among children of all ages, including a 64% decrease in the measles attack rate among children under the age of 9 months. These observations support the one dose, 9 month minimum age measles vaccination policy in tropical Africa.